1. Field of the Invention
The invention relates to electrical connectors, and particularly to an edge connector for interconnecting flexible multiconductor film with LCD or LED display substrates.
2. Description of Related Art
For a number of years now, it has been common practice to use flexible conductor film for interconnecting electronic equipment and units. Such flexible conductor film may be made, for example by etching a copper layer applied to a polyester film serving as a carrier to produce an assembly of several, flexible parallel conductors.
One special field of application is in connections of flexible conductor film with the glass substrates of LCD (liquid crystal display) or LED (light emitting diode) panels. Here, an electrical connection generally has to be produced between a number of parallel conducting strips on the substrate and the respective conductors of the flexible film.
LCD and LED display panels are currently designed in various forms and functions. They include, for example instrument panels in airplanes, cars and ships, and alphanumeric displays in telecommunication equipment. On the substrate of such panels, one or more different functions may be accommodated. These may include speedometer, tachometer, alimeter, as well as indication and warning texts. This means that such a substrate must be provided on its edges with a relatively large number of contact strips or pads. When such a substrate is connected to plug contacts soldered on a printed circuit board, the substrate can no longer be replaced without breaking the soldered connection of one or more plug contacts provided along the edges.
This problem can be avoided by providing the connections with the substrates by means of flexible conductor film. Flexible conductor film can also be etched as a printed circuit and thus also provides attractive possibilities for producing therewith the various externally required connections between the substrate and the equipment for controlling the various functions.
An electrical connector for applying a pressure connection of a flat cable to an LCD or other substrate is disclosed in U.S. Pat. No. 4,379,608 issued Apr. 12, 1983. In the connector of this patent an electrical connection between the contact pads on a glass LCD substrate and the parallel conductors of flexible flat cable is obtained by mechanically pressing the flexible conductors of the flat cable onto the substrate under external spring force. The quality of this connection is largely dependent on the construction elements, which have to ensure that the conductors of the flat cable are accurately positioned relative to the contact pads or strips on the substrate. Since the glass substrates generally possess fairly sharp edges, the thin conductors of the flat cable can easily be damaged. This is true even more in the case of connectors in which the flat cable or other flexible conductor film has to be folded over an edge of the substrate.
In other connections such as the so-called "Zebra" strips, conducting flexible strips are fitted as an intermediate between the contact strips of the display panel and, for example, a printed circuit board. Applying external mechanical pressure on the Zebra strips to produce an electrical connection between the display panel and the printed circuit board cannot be easily or quickly accomplished. Also, various separate auxiliaries such as contact frames, compression means and the like are necessary for positioning of the Zebra strips.